During heart surgery blood that under normal conditions is pumped by the heart is during surgery streamed out of the body to a pumping device (pumping machine), which is configured to provide a blood circulation in the human body that is normally provided by the natural heart. The artificial heart has to maintain the blood flow during the surgery until the natural heart can be re-activated after the end of the surgery.
The heart pulse is deactivated during a heart surgery and the natural heart has completely stopped to pump blood so that the physician can perform the surgical work. As the human body, however, needs the blood to stay alive, the blood is circulated by an external blood pumping device to provide a blood circulation through the body and the blood-pumping device has to perform the functions of the natural heart. In order to provide a pulsatile blood flow existing systems aim to mimic the natural blood flow. However, these systems do not provide the natural pulsating behavior of the heart. For example, one available solution changes the blood streaming from a continuous (non-pulsating) mode to a pulsating mode by controlling the pumping speed, for example, by alternating between a fast and a slow pumping speed. These systems mimic the natural blood pulsing in the body during surgery, but do not provide a real pulse wave. A further disadvantage of these systems is that they need to change permanently the pumping speed (e.g. the rotation velocity of a pumping engine) and thus these systems do not work in a constant operational mode so that the wear and tear of these devices is increased.
Therefore, there is a need for a blood-pumping device providing a pulsating blood flow which comes as close as possible to the natural pulsating blood flow while operating in a constant operational mode. The object of the present invention is therefore to provide a blood-pumping device generating a pulsating blood flow by simple means.